1. Field of the Invention
The present invention relates to a display apparatus including an organic electroluminescence (EL) element.
2. Description of the Related Art
Recently, a display apparatus including organic EL elements, each having an organic compound layer between a pair of electrodes, has been developed with more eagerness. Regarding that type of organic EL element, as discussed in International Publication WO2001/039554, it is known that color purity and luminous efficiency of a luminescent color are improved by utilizing the optical interference effect. In more detail, an optical distance (optical path length) H between two electrodes is expressed by the following formula 1 by using an angle Θ of light emitted from the organic EL element (Θ is 0 degree when the light is visually recognized in a direction rightly facing the element), the sum φ of phase shifts caused when the emitted light is reflected at the two electrodes, and an integer m that is 0 or more. The light of a wavelength λ (resonant wavelength) satisfying the formula 1 is intensified.2H cos Θ=(m+(φ/2π)))×λ  1
Meanwhile, it is also known to dispose a lens on a display apparatus in order to more efficiently take out the light emitted from the organic EL element to the outside. Japanese Patent Laid-Open No. 2004-317559 discloses an organic EL device in which a lens array including lenses and banks serving as light absorbing layers is disposed on an organic EL element. Thus, that related art proposes a technique for increasing contrast by using the lens array.